JP2018202425A - Multiple torsion pipe with spiral groove on inner surface, and method of manufacturing the same - Google Patents

Abstract

To provide a multiple torsion pipe with a spiral groove on an inner surface, which having high dimensional accuracy of a longitudinal groove shape and which has a neat fin shape, and provide a manufacturing method capable of adapting to a slender pipe and excellent in productivity.SOLUTION: In the present invention, a plurality of metal pipes with spiral grooves on inner surfaces, which are different in diameter, which have the plurality of spiral grooves along a lengthwise direction formed at intervals in a circumferential direction on the inner surfaces and which have a spiral fin formed between the adjacent spiral grooves, are provided. The small-diameter pipe with the spiral groove on the inner surface is inserted into the inside of the large-diameter pipe with the spiral groove on the inner surface and integrated. A sacrificial anode layer is formed on the outer periphery of the large-diameter pipe with the spiral groove on the inner surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-twisted tube with an inner surface spiral groove used for a heat transfer tube of a heat exchanger and a manufacturing method thereof.

2. Description of the Related Art Conventionally, a tubular heat exchanger is known that performs heat exchange between a refrigerant flowing inside and outside between an inner channel and a plurality of outer channels disposed around the inner channel in a pipe.
Patent Document 1 discloses a double-pipe heat exchanger that improves heat exchange performance while suppressing an increase in cost in a heat pump heat source machine.

JP-A-2006-99075

 The problem of the double-pipe heat exchanger is to satisfy the demand of suppressing the increase in cost and improving the heat exchange performance. The heat exchange performance can be improved by increasing the length of the double-pipe heat exchanger. On the other hand, there is a problem that the heat exchanger increases in size and increases in material costs. is there.

By the way, the heat transfer tube connecting the condenser for an automobile and the evaporator is constituted by a double tube, and heat exchange is performed between the adjacent warm refrigerant and cold refrigerant through the pipe body while the refrigerant passes through the double tube. Has been made.
In order to efficiently exchange heat between a warm refrigerant and a cold refrigerant in this heat transfer tube, an ideal structure is considered if the double tube has a spiral structure.
However, it is not easy to make each of the double tubes have a spiral structure, and there is a problem that an increase in the size of the heat exchanger and an increase in material costs are inevitable if the heat exchange performance is improved as described above.
In addition, it is desirable that heat exchangers such as automobile condensers and evaporators are exposed to rainwater and are excellent in corrosion resistance.

 The present invention has been made in view of such circumstances, and a structure in which a plurality of internally spiral grooved tubes having a high dimensional accuracy of the groove shape and twist angle in the longitudinal direction is obtained, and production with excellent heat exchange efficiency is obtained. An object of the present invention is to provide a multi-twisted tube with an inner spiral groove that is excellent in properties and corrosion resistance, and to provide a method for manufacturing the same.

The multi-twisted tube with an inner surface spiral groove according to the present invention is made of metal in which a plurality of spiral grooves along the length direction are formed on the inner surface at intervals in the circumferential direction, and a spiral fin is formed between the adjacent spiral grooves. A plurality of inner diameter spiral grooved tubes having different diameters, and a small diameter inner surface spiral grooved tube is inserted and integrated inside a large diameter inner surface spiral grooved tube. A sacrificial anode layer is formed on the outer periphery.
In the multi-twisted tube with an inner surface spiral groove of the present invention, the spiral fin on the inner surface of the large-diameter inner surface spiral groove tube bites into the outer peripheral surface of the inner surface inner spiral groove tube, and the inner surface spiral groove tube with the smaller diameter 1st flow path is formed inside, and the structure by which the 2nd flow path was formed between the said small diameter internal spiral grooved pipe and the said large diameter internal spiral grooved pipe | tube is employable.
In the multiple twisted tube with inner spiral grooves of the present invention, a configuration in which the spiral grooves of the individual inner spiral groove tubes have a constant twist cycle can be adopted.

In the multi-twisted tube with an inner surface spiral groove of the present invention, the sacrificial anode layer may include a Zn content of 0.2% by mass or more and a thickness of 80 μm or more.
In the multiple twisted tube with inner spiral grooves of the present invention, the twist angle of the spiral groove formed on the inner surface of each inner spiral groove tube is 5 to 80 ° with respect to the central axis of each inner spiral groove tube. The set configuration can be adopted.

  The method of manufacturing an inner spiral grooved multiple twisted tube according to the present invention is to prepare a plurality of elementary tubes having different diameters in which a plurality of grooves along the length direction are formed on the inner surface at intervals in the circumferential direction. A small-diameter element tube is inserted into the element tube to form a compound element tube, and the compound element tube is wound around the unwinding side capstan from the introduction side tangential direction while the compound element tube is aligned along the outlet side tangent line. Unwinding and rotating the unwinding side capstan around the axis about the lead-out side tangent, thereby extending the tangent line while rotating the composite element tube around the axis from the unwinding side capstan. An unwinding step of unrolling in the direction of the tube, a torsion pulling step of passing the unwinded union tube through a pulling die and applying a twist while reducing the diameter to form an inner spiral grooved multiple twisted tube, and the inner surface Sacrificial sun on the surface of a multi-twisted tube with spiral grooves Characterized in that it comprises the step of providing a layer.

The manufacturing method of the multiple twisted tube with the inner surface spiral groove according to the present invention can use a raw tube having a straight groove on the inner surface as the groove along the length direction.
The manufacturing method of the multi-twisted tube with an inner surface spiral groove according to the present invention can use a raw tube having an inner surface spiral groove as a groove along the length direction.
In the method for manufacturing an inner spiral grooved multiple twisted tube according to the present invention, the diameter reduction rate by the drawing die can be 5 to 40%.
The method for manufacturing a multi-twisted tube with an inner surface spiral groove according to the present invention can form a sacrificial anode layer containing Zn in an amount of 0.2 mass% or more and having a thickness of 80 μm or more.

The method of manufacturing a multi-twisted tube with an inner surface spiral groove according to the present invention includes: a position where the composite raw tube starts to be wound around the unwinding side capstan; and the composite raw tube is fed from the unwinding side capstan to the drawing die side. By shifting the starting position in a direction parallel to the rotation axis of the unwinding-side capstan, the region between the unwinding-side capstan and the drawing die can be set as a twisting region of the composite element tube.
In the method of manufacturing a multi-twisted tube with an inner surface spiral groove according to the present invention, when the diameter of the composite pipe is reduced while twisting the composite pipe through the composite pipe, the front and rear tensions are applied to the composite pipe. be able to.

  According to the present invention, a structure in which a plurality of metallic inner surface spiral grooved tubes in which a plurality of spiral grooves along the length direction are formed on the inner surface at intervals in the circumferential direction is combined with excellent corrosion resistance. It is possible to provide an unprecedented inner spiral grooved multiple twisted tube having

Sectional drawing which shows 1st Embodiment of the multi-twisted pipe | tube with an internal spiral groove which concerns on this invention. The expanded view which cut out a part of multiple twisted pipe with an inner surface spiral groove of the embodiment. The side view which shows the whole structure of the manufacturing apparatus. The top view which shows the whole structure of the manufacturing apparatus. The top view which shows the state which wound and unwound the pipe | tube with respect to the unwinding side capstan of the manufacturing apparatus. An example of the raw tube supplied to the manufacturing apparatus is shown, (a) is a sectional view, (b) is a transverse sectional view. Sectional drawing which shows the state which inserted the small diameter raw tube inside the large diameter raw tube, and comprised the composite raw tube. Sectional drawing which shows 2nd Embodiment of the multi-twisted pipe | tube with an internal spiral groove which compounded and integrated three types of internal spiral groove pipes from which a diameter differs. Sectional drawing which shows 3rd Embodiment of the multi-twisted pipe | tube with an inner surface spiral groove of the structure which combined and integrated three small diameter inner surface spiral grooved pipe | tubes inside the large diameter inner surface spiral groove tube. The perspective view which extracts and shows three small inner diameter spiral grooved pipes in the multiple twisted pipe with inner surface spiral grooves of the same third embodiment. An example of the heat exchanger which used the multiple twisted tube with an inner surface spiral groove concerning this invention as a heat exchanger tube is shown, (A) is a perspective view, (B) is a partial enlarged view. The specific example of the multiple twisted tube with an inner surface spiral groove manufactured in the Example is shown, (a) is sectional drawing, (b) is the elements on larger scale.

Embodiments of an inner spiral grooved multiple twisted tube, a manufacturing method thereof, and a manufacturing apparatus according to the present invention will be described below with reference to the drawings.
The manufacturing apparatus A (see FIGS. 3 to 4) of the multiple twisted tube with inner surface spiral grooves of the present embodiment has a diameter in which a plurality of linear grooves along the length direction are formed on the inner surface at intervals in the circumferential direction. A composite element tube F in which a plurality of different element tubes (see FIGS. 6 and 7), for example, two elements (element tubes 1 and 8) are combined is applied.
In the manufacturing apparatus A of this example, for example, a raw tube 8 is inserted into the raw tube 1 to form a composite raw tube F, and a constant twist is generated in this, and a small diameter having a spiral groove 2a on the inner surface shown in FIG. This is an apparatus for forming a basic structure of an inner spiral grooved multiple twisted tube 4 in which the inner spiral grooved tube 2 and a large-diameter inner spiral grooved tube 3 having a spiral groove 3a on the inner surface are integrated. After twisting with this manufacturing apparatus A, a Zn sprayed layer, a Zn plated layer, a Zn clad layer, and the like are formed on the outer periphery of the inner spiral grooved tube 3 by an appropriate method such as a spraying method, a plating method, a coating method, or a cladding method. If necessary, heat treatment is performed to diffuse Zn so that the multi-twisted tube 4 with the inner surface spiral groove provided with the sacrificial anode layer 14 can be obtained.

In the multi-twisted tube 4 with the inner surface spiral groove, spiral fins 2b are formed between the inner surface spiral grooves of the small diameter inner surface spiral groove tube 2, and between the inner surface spiral grooves of the large diameter inner surface spiral groove tube 3 between the spiral grooves. Spiral fins 3b are formed.
A sacrificial anode layer 14 is formed on the outer peripheral surface of the inner spiral grooved multiple twisted tube 4, that is, on the outer peripheral surface of the inner spiral grooved tube 3. The sacrificial anode layer 14 is an anticorrosion layer formed, for example, from a Zn sprayed layer, a Zn layer by cladding, or a Zn plating layer, or from which Zn is diffused by thermal diffusion. When the inner spiral grooved tube 3 is formed from aluminum or an aluminum alloy or from an iron-based alloy, the sacrificial anode layer 14 region is electrochemically less preferentially than the region where Zn is not diffused. By corroding, pitting corrosion of the inner spiral grooved tube 3 is prevented. The material constituting the sacrificial anticorrosion layer 14 is preferably provided with a metal layer having a lower potential (lower potential) than the metal material constituting the inner spiral grooved tube 3 to be protected against corrosion.
When Zn is not diffused, it is preferable to provide a thermal spray layer, a clad layer, or the like made of a material containing a large amount of Zn in the material constituting the inner spiral grooved layer 3.

The sacrificial anode layer 14 is formed of, for example, an aluminum alloy layer containing 0.2% by mass or more of Zn and has a thickness of 80 μm or more.
When the Zn content is less than 0.2% by mass, the potential difference from the base material of the inner surface spiral grooved tube 3 (region where Zn is not diffused) decreases, and the corrosion prevention effect tends to be insufficient.
If the thickness of the sacrificial anode layer 14 is less than 80 μm, the sacrificial anode layer thickness is insufficient, and a problem that easily leads to pitting corrosion tends to occur.

In the present embodiment, FIG. 3 shows a side view of the entire structure of the manufacturing apparatus A, and FIG. 4 shows a plan view of the entire structure of the manufacturing apparatus A.
This manufacturing apparatus A is a composite element tube F in which a small-diameter element tube 8 having an equivalent structure is inserted into the element tube 1 having a straight groove (see FIG. 6) 1a formed on the inner surface and combined as shown in FIG. 3, the unwinding side capstan 5 held in a coiled state as shown in FIG. 4, and the composite element tube F unwound from the unwinding side capstan 5 is rotated together with the unwinding side capstan 5. Rotating means 6 is provided. The manufacturing apparatus A also includes a drawing die 7 that passes through the composite element tube F that is fed from the unwinding side capstan 5, and a multi-twisted tube 3 with an inner spiral groove that is twisted and drawn through the drawing die 7. The pull-out side capstan 9 which feeds out while winding is provided.

For example, as shown in FIG. 6, the raw tube 1 has a plurality of straight grooves 1a formed along the length direction on the inner surface of the tube body 1A, and fins 1b are formed between the straight grooves 1a and 1a adjacent to each other in the inner circumferential direction. ing. The raw tube 1 is made of aluminum or an aluminum alloy tube, and has an outer diameter of, for example, about 3 to 20 mm, more specifically about 3 to 12 mm.
An element tube 8 having an outer diameter slightly smaller than the inner diameter of the element tube 1 is inserted into the element tube 1 along the length direction of the element tube 1 to form a compound element tube F. The base tube 8 has the same structure as the base tube 1 and is formed with a slightly smaller outer diameter, and is made of an aluminum or aluminum alloy tube. For example, the outer diameter is about 3 to 20 mm, more specifically about 3 to 12 mm. And it is formed in the outer diameter which can be inserted in the inside of the raw tube 1. In the raw tube 8, as shown in FIG. 7, a plurality of linear grooves 8a are formed along the length direction on the inner surface of the tube main body 8A, and fins 8b are formed between the linear grooves 8a and 8a adjacent in the inner circumferential direction. The same structure as that of the tube 1 is also adopted.

In this embodiment, the elementary tubes 1 and 8 are made of aluminum or an aluminum alloy. However, the elementary tubes 1 and 8 may be made of an iron-based alloy such as a copper alloy or stainless steel. In this embodiment, the raw tubes 1 and 8 made of aluminum or aluminum alloy will be described as an example. However, the multi-twisted tube with an inner spiral groove intended in the present invention can be applied as long as it is a material that can be drawn by a drawing die. Therefore, it goes without saying that the present invention may be carried out using a raw tube made of another metal or alloy such as an aluminum alloy, a copper alloy or an iron alloy.
The outer raw tube 1 and the inner raw tube 8 do not need to be made of the same material, and the raw tube 1 may be made of a copper alloy, and the raw tube 8 may be made of an aluminum alloy. Moreover, even if it is the same aluminum alloy, it is also possible to comprise the raw tube 1 and the raw tube 8 by the aluminum alloy from which a composition differs. In addition, the raw tube 1 and the raw tube 8 are shown as similar-shaped raw tubes in this example, but the widths of the straight grooves 1a and 8a formed on the inner surfaces thereof and the widths and heights of the fins 1b and 8b are shown. The formation pitch and the like may be different between the inner tube 8 and the outer tube 1.

  As shown in FIG. 3, the unwinding-side capstan 5 is horizontally and freely rotatable about its axis on a bearing portion 12 attached to the upper end portions of support members 10 and 11 made of steel that are spaced apart and erected. It is supported by the supported hollow shaft portion 13. The unwinding-side capstan 5, the die 7, and the drawing-side capstan 9 are sequentially arranged along the lengthwise extension line of the hollow shaft portion 13, and the composite element tube F is connected to the hollow shaft portion 13, the unwinding side. The capstan 5, the drawing die 7, and the drawing side capstan 9 are moved and processed in this order. For this reason, in the following description, along the moving direction of the composite element tube F, the upstream side will be appropriately referred to as the front side, and the downstream side will be appropriately referred to as the rear side.

The hollow shaft portion 13 is supported horizontally by bearing members 10 a and 11 a provided at the upper end portion of the column member 10 and the upper end portion of the column member 11, and one end 13 a thereof is upstream from the upper end portion of the column member 10. The other end 13b protrudes from the upper end of the column member 11 to the downstream side outside, and is supported horizontally and rotatably about the axis. A pair of first support frames 15 extending obliquely adjacent to the hollow shaft portion 13 are provided on the other end side of the hollow shaft portion 13, and the unwinding side capstan 5 is supported by the distal end portion 15 a. Yes.
A second support frame 16 is provided on the other end side of the hollow shaft portion 13 so as to extend in an oblique direction with respect to the hollow shaft portion 13, and an extension frame 17 that extends to the distal end side of the second support frame 16 is provided. A weight 18 is attached. The first support frame 15 and the second support frame 16 are connected to the other end 13b of the hollow shaft portion 13 so as to be arranged in a V shape. The second support frame 16 is rotated while being supported in a V shape.

The center part of the disk part 5a of the unwinding side capstan 5 is rotatably supported by the first support frame 15 and the tip part 15a. Further, the unwinding side capstan 5 is supported by the first support frame 15 so that the extension line of the central axis of the hollow shaft portion 13 approximates the tangent line of the outer peripheral edge of the unwinding side capstan 5. For this reason, when the unwinding capstan 5 turns with the rotation of the hollow shaft portion 13, the unwinding side capstan 5 rotates so as to go around the extension line of the central axis of the hollow shaft portion 13. Similarly, with the rotation of the hollow shaft portion 13, the weight body 18 also rotates around the extension line of the central shaft of the hollow shaft portion 13.
In the unwinding side capstan 5, it is comprised so that the composite raw tube F can be wound along the outer periphery of the disk part 5a.

For example, as shown in FIG. 3, when the hollow shaft portion 13 is rotated so that the unwinding side capstan 5 is in the lowest position, the upper portion of the unwinding side capstan 5 is slightly above the uppermost portion of the hollow shaft portion 13. The extension line of the central axis passes. Alternatively, when the hollow shaft portion 13 is rotated so that the unwinding side capstan 5 is in the uppermost position, an extension line of the central shaft portion of the central shaft portion 13 is slightly below the lowermost portion of the unwinding side capstan 5. Pass through.
The hollow shaft portion 13 is formed with an inlet portion 13c having a size capable of inserting the composite element tube F in the opening portion on the one end 13a side. An outlet portion 13d from which F can be drawn is formed.

For this reason, the composite element tube F that has passed through the inside of the hollow shaft portion 13 can be introduced along the tangent line of the outer periphery of the unwinding side capstan 5 and wound around the outer periphery of the unwinding side capstan 5. For example, the composite element tube F wound around the outer periphery of the unwinding side capstan 5 can be unwound from the outer periphery of the unwinding side capstan 5 and led to the drawing die 7 side.
An example of the winding state and the unwinding state of the composite tube F with respect to the unwinding side capstan 5 is simply shown in FIG. In FIG. 5, C indicates the axis of the composite element tube F on the preceding stage wound around the unwinding side capstan 5, and C <b> 1 indicates the axis of the compound element tube F unwound from the unwinding side capstan 5. Yes.

  A first support frame 15 and a second support frame 16 are extended in a V shape on the other end side of the hollow shaft portion 13, and an unwinding side capstan 5 and a weight body 18 are attached to the front end side thereof. However, the weights and the mounting positions of the weight body 18 and the unwinding side capstan 5 are positions where the weight balance is balanced when they rotate. That is, when the weight 18 and the unwinding capstan 5 are turned by the rotation of the hollow shaft 13, the unwinding is performed so that the balance of the rotational moment of both is balanced and the vibration accompanying the rotation of both is as small as possible. The weights and attachment positions of the side capstan 5 and the weight body 18 are adjusted.

A support plate 20 is installed between the upper portion of the support member 10 and the upper portion of the support member 11, a drive motor 21 is attached to the support plate 20, and a power transmission device 22 such as an endless belt is connected to the output shaft 21a of the drive motor 21. Has been. The power transmission device 22 is connected to one end side of the hollow shaft portion 13 positioned above the power transmission device 22, and the hollow shaft portion 13 can be rotationally driven by the rotation of the output shaft 21 a of the drive motor 21.
The drive motor 21, the power transmission device 22, and the hollow shaft portion 13 are configured to rotate the unwinding capstan 5 and the weight body 18 together, and the drive motor 21, the power transmission device 22, and the hollow shaft portion 13 rotate the winding side. Rotating means 6 for rotating the delivery-side capstan 5 is configured.

  The unwinding capstan 5 is provided on the downstream side with respect to the outlet portion 13 d of the hollow shaft portion 13, and the drawing die 7 is supported by the support member 23 on the further downstream side. As shown in FIG. 3, the drawing die 7 is installed at a position where the die hole is located at the same height as the outlet portion 13 d of the hollow shaft portion 13, and between the outlet portion 13 d of the hollow shaft portion 13 and the drawing die 7. It arrange | positions so that the outer periphery of the unwinding side capstan 5 to correspond may a pass line. In this example, the drawing die 7 is attached to the upper end portion of the support member 23 via a hollow support frame 24. Further, a tank 26 and a flexible supply pipe 27 for supplying lubricating oil to the die hole of the drawing die 7 are installed above the support frame 24.

The drawing die 7 has a die hole through which the composite element tube F is inserted, and performs emptying to reduce the outer diameter of the composite element tube F. In the case of the base tubes 1 and 8 made of aluminum or an aluminum alloy, the diameter reduction rate in the drawing die 7 is set to about 5 to 40%. When the diameter reduction rate is too small, the effect of drawing is poor, and it is difficult to obtain a large twist angle, so it is preferable to set it to 5% or more. On the other hand, if the diameter reduction rate is too large, the composite element tube F is liable to break at the processing limit, so 40% or less is preferable.
Further, since the unwinding-side capstan 5 is rotated when the composite element tube F passes through the die hole, the composite element tube F is reduced in diameter by the die hole of the drawing die 7 and is simultaneously twisted. For this reason, the pipes 1 and 8 constituting the composite pipe F are twisted to be processed into a multiple twisted pipe 4 with an inner surface spiral groove shown in FIG.

A drawing-side capstan 9 is provided downstream of the drawing die 7 and supported by a support member 23. The drawing-side capstan 9 is installed in a vertical direction via a horizontal shaft 28 supported by the support member 23 and is rotatable. It is supported. The uppermost part of the drawing-side capstan 9 is installed at the same height as the die hole position of the drawing die 7 so that the inner spiral grooved multiple twisted tube 4 processed by the drawing die 7 is wound around the outer peripheral surface thereof. It has become.
The output shaft 25a of the drive motor 25 for rotational driving is installed on the column member 23 on the opposite side to the side on which the drawing-side capstan 9 is attached so as to be directly connected to the horizontal shaft 28, and the drawing motor-side capstan 9 is driven by the driving motor 25. Can be rotated.

"Production method"
Next, an example of a method for manufacturing the basic structure of the multi-twisted tube 4 with the inner surface spiral groove using the manufacturing apparatus A configured as described above will be described.
As shown in FIGS. 6 and 7, the large-diameter element tube 1 in which a plurality of linear grooves 1a along the length direction are formed on the inner surface at intervals in the circumferential direction, and the inner surface has a length. A small-diameter element tube 8 in which a plurality of linear grooves 8a along the direction are formed at intervals in the circumferential direction is manufactured (element tube extrusion process).
Next, the element tube 8 having a small outer diameter is inserted into the element tube 1 having a large outer diameter as shown in FIG. 7 to form the compound element tube F (composite element tube manufacturing step).
In order to supply the composite element tube F to the manufacturing apparatus A shown in FIGS. 3 to 5, the distal end side of the composite element tube F is inserted into the hollow shaft portion 13 from the inlet portion 13 c of the hollow shaft portion 13, and the hollow shaft portion As shown in FIG. 5, the composite element tube F is pulled out from the 13 outlet portions 13 d and wound around the outer periphery of the unwinding side capstan 5 by one turn. The composite element tube F is unwound from the unwinding side capstan 5 in the tangential direction, inserted into the die hole of the drawing die 7, and the combined element tube F passing through the die hole of the drawing die 7 is drawn out. 9 is wound around one turn or more, and the composite element tube F is pulled out to the downstream side of the extraction side capstan 9. These operations are preparatory operations before the start of the production of the multi-twisted tube with an inner spiral groove.

  After this preparatory work, the front end side and the rear end side of the composite element tube F are each covered with a cylindrical restraint tool 31 as shown in FIG. 4, and a plurality of screw holes formed on the peripheral wall of the restraint tool 31 are inserted into the screw holes. The front end side and the rear end side of the composite element tube F are restrained by screwing 31a. Next, as shown in FIG. 4, a spring-type tension adjusting tool 32 including a coil spring for tension adjustment is connected to the restraining tool 31 on the distal end side of the composite element tube F, and the rear end side of the composite element tube F is connected. The restraint tool 31 is connected with a tension adjusting tool 33 of a spring type provided with a coil spring for tension adjustment.

From this state, processing of the composite element tube F is started. With the start of processing, the composite element tube F is moved at a constant speed to pass through the hollow shaft portion 13 and wound around the unwinding side capstan 5 (unwinding step). The drawing force for passing the composite tube F through the drawing die 7 is given by the rotational force of the drawing-side capstan 9 that is rotated by the drive motor 25.
The drawing die 7 is passed through the composite tube F unwound from the unwinding side capstan 5 and wound around the unloading side capstan 9, and unwinding from the pulling side capstan 9 at a constant speed. Simultaneously with the start of these operations, the hollow shaft portion 13 is rotated at a predetermined speed by the drive motor 21 to rotationally drive the unwinding side capstan 5 and the weight body 18 (twist extraction step).

Further, while monitoring the tension of the tension adjusters 32 and 33, the rear tension when the composite pipe F is wound around the unwinding capstan 5 is adjusted to be constant.
Further, the front tension when the composite element tube F is pulled out from the pull-out side capstan 9 is adjusted to be constant.
For stable application of forward tension, a tensioning device such as a take-up roller or a winch device is arranged downstream of the tension adjusting device 32 and is adjusted so that the tension adjusting device 32 can be pulled at a constant speed. Is preferred. Further, in order to stably add the rear tension, an unwinding device such as an unwinding roller is arranged upstream of the tension adjuster 33 and is adjusted so that the tension adjuster 33 can be fed out at a constant speed. Is preferred.
Alternatively, the tension adjusting tools 32 and 33 are omitted, and a roller for unwinding and a roller for winding are arranged at these positions, and a brake mechanism and a speed adjusting mechanism are incorporated in these rollers, and the downstream side from the drawing die 7. It is mass-produced that a desired forward tension is applied to the front end side of the composite element tube F and a desired rear tension can be applied to the rear end side of the composite element tube F upstream of the drawing die 7. Preferred above.

The die of the drawing die 7 from the unwinding side capstan 5 while applying an appropriate rear tension to the downstream composite element tube F while applying an appropriate rear tension to the downstream composite element tube F around the drawing die 7. Drawing and twisting are simultaneously applied to the composite element tube F passing through the die hole of the drawing die by rotating the unwinding side capstan 5 at the same time as the composite element tube F is passed through the hole.
Usually, when only the twisting force is applied to the thin tube 1 or 8 made of aluminum or aluminum alloy having an outer diameter of about 3 to 20 mm, or about 3 to 12 mm, it easily buckles or breaks. In this manufacturing apparatus A, the pulling force is applied simultaneously with the action of the twisting force to pull out while suppressing breakage due to the twisting. Therefore, a composite composed of the above-described small-diameter aluminum or aluminum alloy pipe 1 and base pipe 8 is used. Even the base tube F can be twisted without breaking.
In this embodiment, the raw tubes 1 and 8 made of aluminum or an aluminum alloy are used. However, the raw tubes 1 and 8 may be made of a copper-based alloy or an iron-based alloy such as stainless steel. , 8 may be made of another kind of metal.

 In this case, a shear stress acts on the composite element tube F in the circumferential tangential direction by twisting, and a twist angle (lead angle) is applied. However, buckling occurs when the shear force exceeds the buckling stress. However, since the shear stress can be reduced by the tensile stress in the longitudinal direction of the element bundle by drawing, the occurrence of buckling of the composite element F can be suppressed. For this reason, even if a large twist angle of about 5 ° to 80 ° is applied to the composite element tube F having the above size, the composite element tube F can be twisted without buckling or breaking.

  As shown in FIG. 3, a region having a length L between the top position of the unwinding-side capstan 5 and the outlet portion of the drawing die 7 is a twisted region of the composite element tube F. In the manufacturing apparatus A, since the length L of the twisted region is made as short as possible, even if a large twist angle is given to the composite pipe F, the pipes 1 and 8 do not break without causing a breakage of 5 ° to 5 °. Twist can be applied up to about 80 °.

The composite element tube F is wound around the unwinding side capstan 5 by one turn, so that the shaft center slightly deviated from the unwinding side axis C along the outer periphery of the unwinding side capstan 5 as shown in FIG. It is sent out along C1.
When the composite element tube F passes through the die hole of the drawing die 7, the center of the composite element tube F and the center of the die hole are aligned so that excessive stress does not act on the composite element tube F. The positional relationship between the hollow shaft portion 13 and the first position so that the unwinding side capstan 5 rotates around the axis C1 around the axial center C1 unwound from the unwinding side capstan 5 as the rotation center. The positional relationship of the support frame 15 and the positional relationship of the unwinding side capstan 5 are preferably matched.
By aligning the center of the composite pipe F and the center of the die hole, even if a large twist is added to the composite pipe F passing through the die hole 7 and processing with a large twist angle is performed, the composite pipe Twist processing can be performed without breaking F.

  The rotation center for rotating the unwinding side capstan 5 coincides with the axial center of the hollow shaft portion 13, but this axial center is aligned with the center of the die hole of the drawing die 7, and along this axial center. Therefore, the center of the composite element tube F needs to move. For this reason, the composite pipe F before being wound around the unwinding side capstan 5 rotates at a position slightly deviated from the axis. For this reason, the composite element tube F before being wound around the unwinding-side capstan 5 rotates eccentrically inside the hollow shaft portion 13, but the inner diameter of the hollow shaft portion 13 is a value that only absorbs this eccentric rotation. Therefore, there is no hindrance to the rotation of the composite element tube F.

As a result of being able to impart a large twist to the composite element tube F passing through the drawing die 7 by performing the twist drawing process described above, the element tubes 1 and 8 are twisted in a spiral shape, and the inner surface has a spiral groove 2a. The inner spiral grooved multiple twisted tube 4 having the structure shown in FIG. 1 can be manufactured by integrating the inner spiral grooved tube 2 and the inner surface spiral grooved tube 3 having the spiral groove 3a on the inner surface.
In this inner spiral grooved multiple twisted tube 4, the inner spiral grooved tube 2 and the inner spiral grooved tube 3 are processed into a spiral shape with a predetermined twist cycle (twist pitch). For this reason, the inner spiral groove 2a formed on the inner surface of the inner spiral groove tube 2 and the inner spiral groove 3a formed on the inner surface of the inner spiral groove tube 3 are formed to have substantially the same twisting cycle.

FIG. 2 shows an example of the internal structure of the inner spiral grooved tube 3 in which the inner spiral groove 3a is formed. An inner surface spiral groove 3a adjacent to the inner periphery in the inner periphery of the inner surface spiral groove tube 3 is formed, and a spiral fin 3b is formed between them.
In this example, the twist angle θ of the inner surface spiral groove 3a and the spiral fin 3b can be manufactured to about 5 ° to 80 °, for example, according to the rotational speed of the unwinding side capstan 5.
In the case of the inner surface spiral grooved tube 3 having the structure shown in FIG. 2, when the peripheral wall is cut open and developed in a planar shape, the length of one cycle of the inner surface spiral groove 3a or the spiral fin 3b with respect to the inner peripheral length a of the tube. In the case of b, the twist angle θ is defined as shown by one apex angle of a right triangle having two sides a and b.
As an example, in the case of an internally spiral grooved tube 3 made of an aluminum alloy having an outer diameter of 8.5 mm, the bottom wall thickness W 1: 0.58 mm shown in FIG. 1, fin height: 0.28 mm, number of strips: 50 leads In the case of the inner surface spiral grooved tube 2 made of an aluminum alloy having an outer diameter of 6.5 mm, the bottom wall thickness W2: 0.35 mm, the fin height: 0.16 mm, the number of strips: 50 pieces can be formed at a lead angle of 17 °.

In the multi-twisted tube 4 with the inner surface spiral groove having the structure shown in FIG. 1, the spiral fins 3b on the inner surface side of the inner surface spiral groove tube 3 bite their tips into the outer peripheral surface of the inner surface spiral groove tube 2 having a small diameter. The inner surface spiral grooved tube 2 and the inner surface spiral grooved tube 3 are integrated. This is because, as shown in FIG. 7, a small diameter pipe 8 is inserted into the large diameter pipe 1, and the whole is drawn through a drawing die 7 and rotated while being reduced in diameter and twisted. As a result, when the large tube 1 is reduced in diameter, the linear fin 1b on the inner surface side of the tube is processed into a spiral shape and is plastically deformed while biting into the outer peripheral surface of the small tube 8 having a small diameter.
For this reason, between the inner surface spiral grooved tube 2 and the inner surface spiral grooved tube 3, a plurality of outer peripheral surfaces of the inner surface spiral grooved tube 2 and a plurality of spiral grooves 3a and spiral fins 3b of the inner surface spiral grooved tube 3 are surrounded. A flow path is formed. For this reason, in the multi-twisted tube 4 with the inner surface spiral groove, the first flow path R1 is formed on the inner side of the inner surface spiral groove tube 2, and between the inner surface spiral groove tube 2 and the inner surface spiral groove tube 3 A plurality of second flow paths R2 are formed. As shown in the cross section shown in FIG. 1, the second flow path R2 is an aggregate of a plurality of small flow paths. To increase the cross-sectional area of the second flow path R2, the inner spiral grooved tube is used. This can be dealt with by setting the height of the three helical fins 3b larger than that of the structure of FIG. 1 and reducing the number of the spiral fins 3b.

In the multi-twisted tube 4 with the inner surface spiral groove, the inner surface spiral groove tube 3 is arranged outside the inner surface spiral groove tube 2, so that the inner surface spiral groove is determined from the lead angle of the spiral groove 2 a of the inner surface spiral groove tube 2. The lead angle of the spiral groove 3a of the attachment tube 3 is formed slightly larger. In other words, the lead angle of the spiral fin 3b of the inner spiral grooved tube 3 is slightly larger than the lead angle of the spiral fin 2b of the inner spiral grooved tube 2.
The magnitude relationship between the lead angle of the spiral groove 2a of the inner spiral groove tube 2 and the lead angle of the spiral groove 3a of the inner spiral groove tube 3 will be shown in an example described later as an example.

Further, according to the above-described manufacturing method, the twist angle of the spiral groove 2a of the inner surface spiral grooved tube 2 made of aluminum or aluminum alloy and the twist angle of the spiral groove 3a of the inner surface spiral groove tube 3 are 5 ° to 40 °. It becomes possible to manufacture to the extent. The pitch of the inner spiral grooved tubes 2 and 3 is determined by the relative relationship between the drawing speed when the composite element tube F passes through the drawing die 7 and the rotation speed of the unwinding side capstan 5. Therefore, if the drawing speed of the composite element tube F and the rotation speed of the unwinding capstan 5 are kept constant, the multi-twisted tube 4 with the inner surface spiral groove having a constant pitch at a constant twist angle along the length direction. Can be obtained.
Further, if the relationship between the drawing speed and the rotational speed of the composite element tube F is periodically changed, it is possible to obtain the multi-twisted tube 4 with the inner surface spiral groove whose pitch and twist angle periodically change in the length direction. .

If the multi-twisted tube 4 with the inner surface spiral groove having the structure shown in FIG. 1 manufactured as described above, in addition to the first flow path R1 inside the inner surface spiral groove tube 2, the inner surface spiral groove tube 2 is provided. When a refrigerant or a heat medium having a different temperature is caused to flow through the second flow path R2 between the pipe 3 and the inner spiral grooved tube 3, heat is generated between the refrigerants or the heat medium having different temperatures or between the refrigerant and the heat medium. Can be exchanged.
In this case, the refrigerant and the heat medium exchange heat efficiently between the refrigerant and the heat medium and the inner surface spiral grooved pipes 2 and 3 due to the presence of the inner surface spiral grooves 2a and 3a.
For this reason, for example, if the multi-twisted tube 4 with the inner surface spiral groove of the present embodiment is applied to a heat transfer tube connecting an automobile capacitor and an evaporator, a heat transfer tube structure having an efficient heat exchange function can be realized. Normally, two heat transfer tubes for connecting the automobile condenser and the evaporator are required. However, in the case of the multi-twisted tube 4 with the inner surface spiral groove of FIG. 1, the first flow path R1 and the second flow path R2 are provided. Since they are provided, both of them can be connected by one inner spiral grooved multiple twisted tube 4.
In this case, in order to equalize the flow rate of the refrigerant or the heat medium flowing back and forth between the condenser and the evaporator, the flow path cross-sectional areas of the first flow path R1 and the second flow path R2 may be made equal. What is necessary is just to enlarge the height and width | variety of the spiral fin 3b of the inner surface spiral grooved tube 3 of a diameter side, and to reduce the number of strips.

In the manufacturing apparatus A of the present embodiment, a preliminary shaping die for shaping for improving the roundness of the composite element tube F may be provided on the front stage side of the hollow shaft portion 13.
Further, in the manufacturing apparatus A of the present embodiment, the raw pipes 1 and 8 constituting the composite raw pipe F are set in advance as inner surface spiral grooved tubes, and these inner surface spiral grooved tubes are combined and passed through the drawing die 7. Thus, a multiple twisted tube with an inner surface spiral groove may be formed by simultaneously applying a reduced diameter and twisting.
Since the sacrificial anode layer 14 is formed on the outer peripheral surface of the inner spiral grooved multiple twisted tube 4 of the present embodiment, when the inner spiral grooved multiple twisted tube 4 is installed in a corrosive environment, the sacrificial anode layer 14 takes precedence. As a result, the pitting corrosion hardly occurs in the inner spiral grooved tubes 2 and 3. For this reason, it is excellent in corrosion resistance and can provide the multiple twisted tube 4 with an internal spiral groove which is hard to generate pitting corrosion.

  The manufacturing apparatus A of the present embodiment can process the composite element tube F, but can also twist one element tube 1 or one element tube 8. For example, the inner surface spiral grooved tube 2 provided with the inner surface spiral groove 2a can be obtained independently by simultaneously applying the diameter reducing process and the twisting process to the single tube 1 using the manufacturing apparatus A.

Since the manufacturing apparatus A can manufacture a single inner surface spiral grooved tube, two inner surface spiral grooved tubes having different diameters are combined to form a composite element tube, and the drawing die 7 is installed as described above. A multiple twisted tube with an inner surface spiral groove may be manufactured by passing it through twisting and drawing.
When passing through the die hole of the drawing die 7, it is possible to manufacture a multi-twisted tube with an inner spiral groove having a twist angle of about 5 ° to 40 ° by processing while accurately drawing and twisting. Depending on the composition of the aluminum alloy constituting the material, the material may have a low elongation and a high risk of fracture. In such a case, it is possible to gradually process in two or three times instead of processing by a single twist drawing process at a target large twist angle. In this way, the multiple twisted tube 4 with the inner spiral groove having a large twist angle can be processed while reducing the possibility of breakage by dividing the processing into a plurality of processes.

Also, after a certain amount of twisted drawing is performed on one large-diameter element tube to be processed into a spiral grooved tube on the inner surface, it is combined with a small-diameter element tube having a straight groove to perform the second twist-drawing process. good.
In this case, if a lead angle of 10 ° was given by the first twist drawing process, and the twist drawing process which gives a lead angle of 10 ° by the second twist drawing process is performed, the inner surface on the large diameter side The inner surface spiral groove with a lead angle of the spiral fin (spiral groove) formed on the spiral grooved tube of 20 ° and the lead angle of the spiral fin (spiral groove) formed on the inner diameter spiral groove tube on the small diameter side with 10 °. An attached multiple twisted tube can be manufactured.
In addition, after a certain amount of twisting and drawing is performed on one small-diameter element tube to form an internally spiral grooved tube, the second twist-drawing process is performed in combination with a large-diameter element tube having a straight groove. The lead angle of the spiral fin (spiral groove) formed on the inner diameter spiral groove tube on the small diameter side is 20 °, and the lead angle of the spiral fin (spiral groove) formed on the inner diameter spiral groove tube on the large diameter side is 10 °. It is possible to manufacture a multiple twisted tube with an inner spiral groove having a 0 °.

If a multiple twisted tube with an inner spiral groove is manufactured using the manufacturing apparatus A as described above while adjusting the state of the groove of the raw tube, the lead angle and the smaller diameter side of the large-diameter side spiral fin (spiral groove) It is possible to manufacture a multi-twisted tube with an inner surface spiral groove having a structure in which the size relationship of the lead angles of the spiral fins (spiral grooves) is freely adjusted.
Further, a drawing die for shaping may be further provided on the downstream side of the drawing side capstan 9 to perform finish drawing for increasing the roundness of the multi-twisted tube 4 with the inner surface spiral groove.
In order to provide a drawing die for finishing drawing, a column member having the same shape as the column member 23 shown in FIG. 3 is provided on the downstream side of the column member 23, and a support frame having the same shape as the support frame 24 is separately provided above the column member. It is preferable to provide a drawing die for finish molding on the support frame.
The roundness of the inner spiral grooved multiple twisted tube finally obtained by passing the inner spiral grooved multiple twisted tube after passing through the drawing side capstan 9 through a drawing die for finishing molding is improved. A multi-twisted tube with an internal spiral groove can be provided.

“Second Embodiment”
In the previous embodiment, the elementary tubes 1 and 8 were combined and integrated, and twisting and drawing were performed to obtain an inner spiral grooved multi-twisted tube 4, but the number of applications when integrating the elementary tubes is as follows: Any number can be selected.
For example, a triple pipe is formed by inserting three elementary pipes having different diameters, and the triple pipe is drawn while being twisted by the manufacturing apparatus A, whereby the inner surface of the triple pipe structure shown in FIG. A multi-twisted tube 34 with spiral grooves can be manufactured.
An inner spiral grooved multiple twisted tube 34 according to the second embodiment shown in FIG. 8 is twisted by combining a single larger diameter pipe outside the inner spiral grooved multiple twisted tube 4 having the structure shown in FIG. And a structure manufactured by drawing.

In the structure shown in FIG. 8, the innermost spiral grooved tube 35 having the largest diameter has an inner surface spiral groove 35 a and a spiral fin 35 b, and the spiral fin 35 b is bited into the outer peripheral surface of the inner surface spiral grooved tube 3. Between the inner surface spiral grooved tube 3 and the inner surface spiral grooved tube 35, a plurality of third flow paths R3 having a shape surrounded by the spiral fins 35b adjacent to the outer peripheral surface of the inner surface spiral grooved tube 3 are formed. .
A sacrificial anode layer 14 is formed on the outer peripheral surface of the large-diameter inner surface spiral grooved tube 35. The sacrificial anode layer 14 is a layer equivalent to the previous embodiment.

In the structure shown in FIG. 8, since the third flow path R3 is provided in addition to the first flow path R1 and the second flow path R2, a structure corresponding to three types of refrigerants or heat media can be provided.
In addition, when manufacturing the multi-twisted tube 34 with the inner surface spiral groove of the triple tube structure, the tube is manufactured after combining a tube having a smaller diameter than the tube 1 with respect to the combined tube F of the tube 1 and 8 shown in FIG. The apparatus A may be used for twisting and drawing.
In the inner spiral grooved multiple twisted tube 34, the sacrificial anode layer 14 region is preferentially corroded over the region where Zn is not diffused, thereby preventing pitting corrosion of the inner surface spiral grooved tube 35. For this reason, the multiple twisted tube 34 with the inner surface spiral groove excellent in corrosion resistance can be provided.

Further, as described above, any of a pipe having a straight groove and a pipe having an inner spiral groove may be used as the pipe used, for example, the lead angle of the spiral fin 2b and the lead angle of the spiral fin 3b. The lead angle of the spiral fin 35b can be sequentially controlled to different angles.
For example, an element tube having a straight groove is used as the element tube with the smallest diameter, an inner spiral grooved tube with a lead angle of 10 ° is used as the second largest element tube, and an inner surface with a lead angle of 20 ° is used as the largest element tube. Using a spiral grooved tube, the manufacturing apparatus A is used for twisting and drawing under the condition of giving a lead angle of 10 °.
By manufacturing in this way, the lead angle of the smallest inner spiral groove tube is 10 °, the lead angle of the second largest inner spiral groove tube is 20 °, and the lead angle of the largest inner spiral groove tube is It is possible to obtain a multi-twisted tube with an inner surface spiral groove excellent in corrosion resistance of a triple tube structure of 30 °.

“Third Embodiment”
In the previous embodiment, a single pipe 8 is inserted into the pipe 1 and a drawing process and a twisting process are added. However, a composite pipe in which a plurality of pipes 8 are inserted into the pipe 1. It is also possible to manufacture a multi-twisted tube with an inner spiral groove by using the manufacturing apparatus A.
For example, a plurality of (for example, three) element tubes having a smaller diameter are inserted into one element tube 1 to produce a compound element tube, and the entire compound element tube is subjected to drawing and twisting. Thus, a multi-twisted tube with an inner spiral groove can be manufactured.

In FIG. 9, three inner surface grooved pipes with a small diameter are inserted into one inner surface grooved pipe with a larger diameter, and the whole is drawn and twisted using the manufacturing apparatus A. This embodiment of the obtained multi-twisted tube with an inner surface spiral groove is shown.
The inner spiral grooved multiple twisted tube 40 of this embodiment is provided with a large-diameter inner surface spiral grooved tube 41 on the outermost layer, and three twisted small-diameter inner spiral grooved tubes 42 inside thereof. Is provided.
A plurality of spiral grooves 41a and spiral fins 41b are provided on the inner surface of the large-diameter inner surface spiral grooved tube 41 at a predetermined pitch in the length direction. A plurality of spiral grooves 42a and spiral fins 42b are provided at predetermined pitches in the length direction on the inner surfaces of the three small diameter inner spiral groove tubes 42, respectively. It is formed in a triangular ellipse shape.
A sacrificial anode layer 14 is formed on the outer peripheral surface of the outer inner surface spiral grooved tube 41. The sacrificial anode layer 14 is a layer equivalent to the previous embodiment.

FIG. 10 is a perspective view showing a state in which the innermost spiral grooved tube 41 of the outermost layer is removed and three inner spiral grooved tubes 42 having a stranded structure housed therein are taken out. The three inner spiral grooved tubes 42 are stranded at a predetermined cycle as shown in FIG.
In the multiple twisted tube 40 with the inner surface spiral groove of this embodiment, the period (twisted wire pitch) of the spiral groove 42a formed on the inner surface of the innermost surface spiral grooved tube 41 of the outermost layer and the inside thereof are stranded. The period (twisted wire pitch) of the three inner surface spiral grooved pipes 42 is substantially the same period.
This is obtained by inserting three small-diameter inner-grooved pipes into one large-diameter inner-grooved pipe and drawing and twisting the whole using the manufacturing apparatus A. This is because. A first flow path R1 is formed inside the small-diameter inner surface spiral grooved tube 42, inside the large-diameter inner surface spiral grooved tube 41 and outside the small diameter inner surface spiral grooved tube 42. The flow path R2 is formed.
The twist angle θ in the inner spiral grooved multiple twisted tube 40 of the present embodiment can be manufactured to about 5 ° to 80 °, for example, according to the rotational speed of the unwinding side capstan 5 using the manufacturing apparatus A.

The multi-twisted tube 40 with the inner surface spiral groove having the structure shown in FIGS. 9 and 10 can be applied to a heat transfer tube connecting an automobile capacitor and an evaporator. By using the three first flow paths R1 and the second flow path R2 individually, a structure including a heat transfer tube having an efficient heat exchange function can be realized. Normally, two heat transfer tubes for connecting the automobile capacitor and the evaporator are required. However, in the case of the multi-twisted tube 40 with the inner surface spiral groove shown in FIGS. 9 and 10, the first flow path R1 and the second flow tube are used. The flow paths R2 can be used separately, and both can be connected by a single multi-twisted tube 40 with an inner surface spiral groove.
In that case, since the refrigerant or the heat medium flowing through the first flow path R1 can efficiently exchange heat with the refrigerant or the heat medium flowing through the second flow path R2, a connection with high heat exchange performance can be made as a heat transfer tube.
Further, in the inner spiral grooved multiple twisted tube 40, the sacrificial anode layer 14 region is preferentially corroded over the region where Zn is not diffused, thereby preventing pitting corrosion of the inner surface spiral grooved tube 41. For this reason, the multiple twisted tube 40 with an inner surface spiral groove excellent in corrosion resistance can be provided.

Moreover, the period of the spiral groove 42a formed inside the inner surface spiral grooved tube 42 shown in FIGS. 9 and 10 and the stranded wire pitch of the inner surface spiral groove tube 42 may not be equal.
As described above, the element tube having the straight groove on the inner surface and the element tube having the spiral groove on the inner surface can be combined and applied to the manufacturing apparatus A. A multi-twisted tube with an inner surface spiral groove having three inner surface spiral groove tubes having a spiral groove having a period different from the stranded wire pitch is inserted into the tube and subjected to drawing and twisting using the manufacturing apparatus A. Can be obtained.

FIG. 11 shows an example of a heat exchanger using any one of the inner spiral grooved multiple twisted tubes 4, 34, 40 described above as the heat transfer tube 50. The heat exchanger 51 of this example includes a heat sink. A plurality of fins 52 are arranged in parallel at predetermined intervals, and the heat transfer tubes 50 bent in a U-shape are inserted into insertion holes 52a formed in the fins 52.
For example, the heat transfer tube 50 is disposed so as to pass through the insertion holes 52a of the plurality of fins 52 in the straight tube portion 50A, and the open ends of the straight tube portion 50A shown in FIG. By doing so, a serpentine heat transfer tube can be configured.
For example, the fin 52 is made of aluminum or an aluminum alloy plate, and a part thereof is subjected to burring or the like to form an insertion hole 52a, and a flange part 52b is formed at the inner peripheral edge of the insertion hole 52a.

The heat exchanger 51 having a high heat exchange efficiency can be provided by applying any one of the multi-twisted tubes 4, 34, and 40 with the inner surface spiral groove in the heat exchanger 51 having the structure shown in FIG.
Further, since the sacrificial anode layer 14 is formed on the outer peripheral surface of the multi-twisted tubes 4, 34, 40 with the inner spiral groove, when the heat exchanger 51 is installed in a corrosive environment, the sacrificial anode layer having a low potential is formed. 14 is preferentially corroded. As a result, a corrosion product is generated on the surface of the inner spiral grooved multiple twisted tubes 4, 34, 40, and this corrosion product is a portion where the inner spiral grooved multiple twisted tubes 4, 34, 40 pass through the flange portion 52b. Also generate.
As a result, it is possible to fill the gap where the inner spiral grooved multiple twisted tubes 4, 34, 40 pass through the flange portion 52b with the corrosion product. It is possible to prevent rainwater and the like from entering through the gap.
When rainwater or the like enters between the fins 52 arranged in parallel to form water droplets and the water droplets block the gaps between the fins, the blowing resistance when the air is blown to the fins 52 is increased, and the heat exchange efficiency of the heat exchanger 51 is increased. Decreases. For this reason, the sacrificial anode layer 14 formed on the outer peripheral surface of the multiple twisted tubes 4, 34, 40 with inner spiral grooves enhances the corrosion resistance of the heat exchanger 51 and also suppresses the efficiency reduction of the heat exchanger 51.

 An A3003 alloy with an outer diameter of 10.0 mm, an inner diameter of 9.0 mm, and a fin height of 0.25 mm and a number of 50 straight grooves formed on the outer tube, an outer diameter of 8.5 mm and an inner diameter of 7.8 mm A composite element tube F having the configuration shown in FIG. 7 was prepared using A3003 having a fin height of 0.2 mm and straight grooves with 55 grooves formed on the inner tube. The composite element tube F is twisted and drawn under the conditions of a drawing die hole diameter φ8.5 mm and a drawing speed 1.0 m / min using the manufacturing apparatus A shown in FIGS. A twisted tube was manufactured.

First, increase the revolution length of the machining area and the revolution speed of the unwinding capstan to grasp the relationship between the limit twist angle (maximum twist angle that can be twisted without buckling), the machining area length is 160 mm, and the rear tension is 5 When it was produced under the above conditions at ˜20 kg, a multi-twisted tube with an inner surface spiral groove having a cross section as shown in FIG. 1 could be produced. A Zn sprayed layer having a thickness of 15 μm was formed on the outer peripheral surface of the outer tube by Zn spraying.
FIG. 11 shows a cross-sectional view (see FIG. 11A) and a partially enlarged view (see FIG. 11B) of a sample manufactured under the above conditions.
The obtained multi-twisted tube with an inner surface spiral groove has an outer diameter of 8.45 mm, a thickness of 0.55 mm, a fin height of 0.2 mm, an inner diameter of 50 grooves, an outer diameter of 6.95 mm, a wall thickness of 0.40 mm, The inner spiral grooved tube with a fin height of 0.2 mm and the number of grooves of 55 was integrated, and was an inner spiral grooved multiple twisted tube having a Zn sprayed layer on the outer peripheral surface.

  Next, when configuring a composite pipe made of an aluminum alloy equivalent to the previous example, change the outer diameter, bottom wall thickness, fin height, and lead angle of the small diameter pipe and the large diameter pipe. A plurality of multiple twisted tubes with inner spiral grooves were prepared. Table 1 below shows the measurement results of the outer diameter, bottom wall thickness, fin height, and lead angle of the obtained multi-twisted tube with inner spiral grooves.

As shown in Examples 1 to 12 of Table 1, it is a double pipe structure made of aluminum alloy, and has an outer diameter of 5-12 mm of the inner diameter spiral grooved tube on the large diameter side, and an inner surface spiral grooved tube on the small diameter side And an inner spiral grooved multiple twisted tube having an outer diameter of 3.6 to 10.6 mm and a lead angle of 10 to 20 ° could be manufactured.
As shown in these Examples 1 to 12, an inner spiral grooved multi-twisted tube having an inner spiral grooved tube made of an aluminum alloy that is extremely thin and easily buckled, such as an outer diameter of 3.6 to 12 mm. 3 to 5 could be manufactured by the manufacturing apparatus A having the configuration shown in FIG.

  A ... Manufacturing apparatus, F ... Composite raw pipe, L ... Length of twist processing region, R1 ... First flow path, R2 ... Second flow path, 1 ... Raw pipe, 1a ... Linear groove, 2 ... Internal spiral Grooved tube, 2a ... spiral groove, 2b ... spiral fin, 3 ... inner surface spiral groove tube, 3a ... spiral groove, 3b ... spiral fin, 4 ... inner spiral groove multiple twisted tube, 5 ... unwinding side capstan, DESCRIPTION OF SYMBOLS 6 ... Rotating means, 7 ... Drawing die, 8 ... Elementary pipe, 8a ... Straight groove, 9 ... Drawing side capstan, 10a, 11a ... Bearing part, 12 ... Bearing part, 13 ... Hollow shaft part, 13a ... One end, 13b ... the other end, 14 ... sacrificial anode layer, 15 ... first support member, 16 ... second support member, 18 ... weight body, 21 ... drive motor, 22 ... power transmission device, 28 ... horizontal shaft, 31 ... cylindrical member, 31a ... thumbscrew, 32 ... tension adjuster (forward tension applying means), 33 ... tension adjuster (rear tension applying hand) ), 34 ... Multi-twisted tube with inner spiral groove, 35 ... Tube with inner spiral groove, 35a ... Helix groove, 35b ... Helical fin, 40 ... Multi-twisted tube with inner spiral groove, 41 ... Spiral tube with inner spiral groove, 41a ... Spiral groove, 41b ... spiral fin, 42 ... pipe with inner spiral groove, 42a ... spiral groove, 42b ... spiral fin.

Claims (12)

  A plurality of metal inner surface spiral grooved pipes having different diameters are formed, in which a plurality of spiral grooves along the length direction are formed on the inner surface at intervals in the circumferential direction, and spiral fins are formed between the adjacent spiral grooves. A small-diameter inner surface spiral groove tube is inserted and integrated inside the large-diameter inner surface spiral groove tube, and a sacrificial anode layer is formed on the outer periphery of the large-diameter inner surface spiral groove tube. Multi-twisted tube with inner spiral groove.   The spiral fin on the inner surface of the large-diameter inner surface spiral groove tube is bitten into the outer peripheral surface of the inner surface inner spiral groove tube, and a first flow path is formed inside the small-diameter inner surface spiral groove tube, The multiple twisted tube with an inner surface spiral groove according to claim 1, wherein a second flow path is formed between the small diameter inner surface spiral grooved tube and the large diameter inner surface spiral grooved tube.   The multi-twisted tube with inner spiral grooves according to claim 1 or 2, wherein the spiral grooves of the individual inner spiral groove tubes have a constant twist cycle.   The multi-twisted tube with an inner surface spiral groove according to any one of claims 1 to 3, wherein the sacrificial anode layer includes 0.2 mass% or more of Zn and has a thickness of 80 µm or more.   2. The twist angle of the spiral groove formed on the inner surface of each individual inner surface spiral groove tube is set to 5 to 80 degrees with respect to the central axis of each inner surface spiral groove tube. The multi-twisted tube with an inner surface spiral groove according to claim 4.   Prepare multiple pipes with different diameters with multiple grooves along the length direction on the inner surface spaced in the circumferential direction, and insert the small diameter pipe into the large diameter pipe Forming a pipe, winding the composite element pipe along the derivation side tangent while winding the composite element pipe around the unwinding side capstan from the introduction side tangential direction, and unwinding the unwinding side capstan with the derivation side tangent An unwinding step of unwinding the unwound tube in the extending direction of the tangential line while rotating the composite union tube around the axis from the unwinding side capstan by rotating around the shaft as an axis. Twisting and pulling a composite element tube through a drawing die to give a twist while reducing the diameter to form a multiple twisted tube with an inner surface spiral groove, and a step of providing a sacrificial anode layer on the surface of the inner surface spiral grooved multiple twist tube Internal screw characterized by comprising Method for manufacturing a grooved multi torsion tube.   The method of manufacturing a multi-twisted tube with an inner surface spiral groove according to claim 6, wherein a raw tube having a linear groove on the inner surface is used as the groove along the length direction.   The method of manufacturing a multi-twisted tube with an inner surface spiral groove according to claim 6, wherein an element tube having an inner surface spiral groove is used as the groove along the length direction.   The method for producing a multi-twisted tube with an inner surface spiral groove according to any one of claims 6 to 8, wherein the diameter reduction rate by the drawing die is 5 to 40%.   10. The multi-twisted tube with inner spiral grooves according to claim 6, wherein a sacrificial anode layer containing 0.2 mass% or more Zn and having a thickness of 80 μm or more is formed. Method.   A position parallel to the rotation axis of the unwinding side capstan is a position at which the composite union tube starts to be wound around the unwinding side capstan and a position at which the composite union tube starts to be fed from the unwinding side capstan to the drawing die side. The inner surface according to any one of claims 6 to 10, wherein a region between the unwinding side capstan and the drawing die is used as a twist processing region of the composite element pipe by shifting to the inner side. A method of manufacturing a multi-twisted tube with spiral grooves.   The front tension and the rear tension are added to the composite pipe when the diameter of the composite pipe is reduced by twisting the composite pipe through the drawing die. The manufacturing method of the multi-twisted pipe | tube with an internal spiral groove as described in claim | item.